Foldable square



S. 0. THORELL.

FOLDABLE SQUARE.

APPLICATION FILED APRA. 191s.

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rammed May 11,1920.

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S. 0. THORELL.

FOLDABLE SQUARE.

APPucATlon man APRA. 191e.

.Patented May 11, 1920.

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SVV'ANl O. THORELL, OF`DENVER, COLORADO,

FOLDABLE SQUARE. v

Specification of Letters Patent.

Patented May 11, 1920.

Application led April 4, 1918. Serial No. 226,686.

To all 'whom t may concern Be it known that I, SWAN O. THORELL, a citizen of the United States, residing at Denver, in the countyof Denver and State of Colorado, have invented certain new and useful Improvements in Foldable Squares; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to instruments of precision and more particularly to a foldable square. It has been proposed to fold, or relatively collapse, the angularlyv disposed blades or legs of squares but because of this foldable construction the parts are likely to have a slight play, especially when in the angularly set position, and thus this destroys the absolute accuracy of the square.

It is'one of the objects of the present invention to provide for the accuracy of the instrument when it is adjusted as a square and it is a further object of the invention to provide for the ready locking of the foldable parts of the square in either set or collapsed position. It is a further object of the invention to provide a device of this type which will not only be as substantially accurate as a rigid square but which will be easily adjustable, readily locked in either of its positions and which shall be simple, practicable, inexpensive and durable.

With these and other 'objects in View, as will be readily understood by those versed in the art, the invention consists of a square having relatively lfoldable parts and in means for locking the parts and in details and arrangements as described hereinafter with relation to a form of the invention illustrated in the accompanying drawing, in which- Figure l is a plan View of the jointed ends of a fragment of the square,

Fig. 2 is a similar view taken from the opposite side of the square,

Fig. 3 is a transverse section on line 3 3 of Fig. l,

Fig. l is a section on line 1 1-4 of Fig. 2,

Fig. 5 is a section on line 5-5 of Fig. 2,

Fig. 6 is a p lan view of the unfolded or set members looking toward the same side as in Fig. l,

Fig. 7 is a sectional view on'line 7-7 of Fig. 6,

Fig.`8 is a fragmentary view showing the spring detent as sprung upwardly to release the members,

Fig. 9 is a bottom plan view of Fig. 6, and Fig. l() is a section on line lO-p-l() of 9. nl its illustrated embodiment, the inven tion comprises what Amay be termed an elbow arm, A, and a straight blade, B. 4The short arm of the elbow member, A, extends at right angles from the main body and is shown as of about one-half the thickness of main member, A, so that it will overlap the complementary recessed portion of the adj acent end of the blade, B, and so that the top and bottom surfaces of these members A and B are respectively flush. The elbow arm and the recessed end of the member, B, are pivotally connected together by means of a suitable device in the form of a screw, 2, having a large flat end, 8, overlapping a seat countersunk in the short arm of the arm, A, the threads of the screw engaging in the adjacent end of the blade, B. For the purpose of securing accuracy of adjustment of the parts and to eleminate unnecessary play, the elbow arm, A, isl provided at the end of its elbow with an arcuate edge, 4,.

having a lip, 5, adapted to enter an undercut arcuate seat or groove, A6, concentric to the center of the screw, 2, and formed in the adjacent edgeof the blade, B. To limit the outward swinging movement of the blades about the pivot screw, 2, the arcuate edge intersects a straight transverse shoulder, 7, of the elbow arm and this is adapted to be abutted by a similar straight shoulder, 8, at the complementary portion of the blade, BA Coperative with the inter-engaged lip, 5, and groove, 6, to guide the folding movement, the end of theblade, B, which is diametrically opposite to the groove, 6, is provided as shown in Fig. 7 with a lip, l0, running in a groove, il, curved concentrically with the axis of the screw, 2, so that when the members A-B are set at right angles to each other, the parts are held against relative play. f

Une the important features of the pres- -ent invention resides in means for readily locking the arm, A, and the blade, B, either in the set right angular position, Figs. 6 and 9, or in the folded position, Figs. i and 2. To effectually, easily, and inexpensively, secure the locking of these members, there is clearly shown in Figs. 7 and 8 a device comprising a flat spring finger or detent, 15, lwhich is l riveted or otherwise secured at one end at,

16, to thebody of the blade, B, while its opposite and yielding end is adapted to be pressed upwardly from the chamber 1T, in wl 'ch it may lie flush with the top planeV of the blade, B, by the application of pressure, as, for instance, from one ol the lingers or thumb against a button, 19, secured to the lower face of the linger, 15, and playing in an aperture, 20, provided therefor in the underlying Vportion of the blade, B. Y

The end ol' the linger, 15, may be, and in the present case is, shown as being beveled downwardly and rearwardly, as clearly appears at Fig. 8. When the square is folded, as in 1, the end ol the iinger, 15, will rest against the adjacent edge of the arm of the lelbow member, A, and will thus prevent movement of that arm and thereby will act as a loch, locking this vsquare in folded position. VJ hen the end ci the finger, 15, is beveled as here shown, it is found preferable to provide an indentation, or relge of therarm oi the cess, 21, in the said et elbow, in which recess the extreme end oil1 the linger 15 will rest when the square is in folded position. For locking the square in open position a notch, 22, is provided inthe said short arm of the elbow member, A, said notch being constructed to exactly accommodate the end of the linger, 15, when the arms are in right angle position, as shown in Figs. 6 and 9. Y

It will be evident thatwhen the square is in 'folded position the spring linger, 15, will -automatically spring into engagement with the edge of the short arm and loclr thc saine as hereinabove described and, likewise, when the arms are in right angle position this nger will automatically engage the notch 22 and lock the square in open position, as above described. To change the square from one position to the other it is only necessary to raise the end of the spring linger, 15, by pressure on the button, 19, as indicated at liig. 8. The spring, 15, in order that it may, when in normal position, be flush with the surface ci' the blades, is preferably mounted in a groove or depression, 15a, in the blade, B, and, in order that the locking of the arms in right angle position may be more secure and exact, this groove is so constructed that when the blades are in right angle position the notch, 22, and the groove, 15a, will be in exact alinement so that the spring, l5, will lit snugly in both continuously.

That is claimed is Y 1. A square having a pair'of flat pivoted members to open or close, one otV the menr bers having a short elbow arm, the transverse edge of'said short arm and the adjacent part of the other member being provided with interlocking, undercut and over lying guide means concentric with the axis needles;

of the pivot, the elbow having an inside edge perpendicular' toits blade, and a detent relatively engageable with the inside and trans verse edges.

2. A. square having a pair of iiat pivoted members to open or close, one of the members having a short elbow arm having an arcuate transverse edge deeply notched, said short arm and the adjacent end of the other Vmember being provided with interlocking, undercut and overlying guide means concentric with the axis of pivot, and a resilient nger attached to the pivoted end of one member for interlocking with deep notch of the short arm and engaging a notch in a side of the elbow Vwhen the arms are in the opened or closed positions. y

3. n. square having blade members, orc 'ot said members having an elbow with a notch in one edge thereof, and theV other member lia-ving a countersu'nl( detent adapted to engage said Ynotch when the blades are in right angle position, said detent being likewise adapted to engage said elb iv member when the square is in folded position, the datent being` operable by pressure applied thereto 'from the opposite 'face ol the member on which it is mounted, the member carrying the detent having a nn ger hold provided for access-tothe detent.V Y

l. A square having blade members mutually recessed and overlapping jointed ends whereby the blades may be adjusted in parallel or right 'angular relation, one ot said members having an 'elbow with an edge thereof notched and the other member having a detent to engage said notch, to loch the members in right angular relation, said detent being countersunl and having a part exposed at its opposite base Yof its carryingi member to be lifted from its sure against said part.

5. A square having a pairot flat pivoted members adapted to be disposed either parallel or perpendicular to each other, each of said members being provided with a straight edge, one of the members havingan elbow with one edge perpendicular to said straight edge and an arcuate edge around its end and'opposite to thestraight edge, a'stop shoulder at one side of the arcuate edge, the other member having a stop shoulder engageable with the aforesaid stop shoulder, said `short arm and the adjacent 'end ci? Vthe other arm provided with interlocking, un dercutting Vand underlying, vguide means at the arcuate edge and concentric with the anis ot the pivot, and a resilient finger attached to thc pivot end of one member for interlocking with the arcuate edile of the short elbow and also with the straight edge. Y

In testimony whereof he alixes his 'signai ture. Y Y Y seat by prcs- SWAN O.v THOR 

